Execution of a target system that includes a component model

ABSTRACT

Methods and systems for the design and execution of an aerospace or aeronautic system are provided. The aerospace or aeronautic system may incorporate planetary environment models and models of equations of motion. The planetary environment models mathematically represent planetary environment specifications, such as atmosphere and wind. Atmosphere models include standard day atmosphere models and non-standard day atmosphere models, and wind models include continuous wind turbulence models and discrete wind turbulence models. The models of equations of motion include models of three-degree-of-freedom equations of motion with variable mass and models for six-degree-of-freedom equations of motion with variable mass. As a result, the present invention can design and execute a target system more accurately than the conventional system that provides only standard day planetary environment models, continuous wind turbulence models, or fixed mass equations of motion models.

RELATED APPLICATIONS

This application claims the benefit of U.S. patent application Ser. No.10/678,718 filed on Oct. 3, 2003 issued as U.S. Pat. No. 7,720,657, thecontents of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to block diagram executionenvironments and more particularly to methods and systems for the designand execution of a target system that includes a component model.

BACKGROUND OF THE INVENTION

Computer systems may include interactive software tools that provideenvironments for designing and executing digital models of electrical,electronic or mechanical devices prior to producing actual physicaldevices. The design and execution of a target system is performed oncomputers using the software tools, such as Simulink® and MATLAB®, bothfrom The MathWorks Inc. of Natick, Mass.

Various classes of block diagrams describe computations that can beperformed on application specific computational hardware, such as acomputer, microcontroller, FPGA, and custom hardware. Classes of suchblock diagrams include time-based block diagrams such as those foundwithin Simulink from the MathWorks, Inc. of Natick Mass., state-basedand flow diagrams such as those found within Stateflow® from theMathWorks, Inc. and data-flow diagrams. A common characteristic amongthese various forms of block diagrams is that they define semantics onhow to execute the diagram.

Historically, engineers and scientists have utilized time-based blockdiagram models in numerous scientific areas such as Feedback ControlTheory and Signal Processing to study, design, debug, and refine dynamicsystems. Dynamic systems, which are characterized by the fact that theirbehaviors change over time, are representative of many real-worldsystems. Time-based block diagram modeling has become particularlyattractive over the last few years with the advent of software packagessuch as Simulink from The MathWorks, Inc. Such packages providesophisticated software platforms with a rich suite of support tools thatmakes the analysis and design of dynamic systems efficient, methodical,and cost-effective.

A dynamic system (either natural or man-made) is a system whose responseat any given time is a function of its input stimuli, its current state,and the current time. Such systems range from simple to highly complexsystems. Physical dynamic systems include a falling body, the rotationof the earth, bio-mechanical systems (muscles, joints, etc.),bio-chemical systems (gene expression, protein pathways), weather andclimate pattern systems, etc. Examples of man-made or engineered dynamicsystems include: a bouncing ball, a spring with a mass tied on an end,automobiles, airplanes, control systems in major appliances,communication networks, audio signal processing, nuclear reactors, astock market, etc. Professionals from diverse areas such as engineering,science, education, and economics build mathematical models of dynamicsystems in order to better understand system behavior as it changes withthe progression of time. The mathematical models aid in building“better” systems, where “better” may be defined in terms of a variety ofperformance measures such as quality, time-to-market, cost, speed, size,power consumption, robustness, etc. The mathematical models also aid inanalyzing, debugging and repairing existing systems (be it the humanbody or the anti-lock braking system in a car). The models may alsoserve an educational purpose of educating others on the basic principlesgoverning physical systems. The models and results are often used as ascientific communication medium between humans. The term “model-baseddesign” is used to refer to the use of block diagram models in thedevelopment, analysis, and validation of dynamic systems.

Engineers, analysts, and researchers in the aerospace and aeronauticindustry are often faced with relatively small budgets when designingaerospace and aeronautic systems, such as aircraft, spacecraft,missiles, satellites, weapons, and unmanned airborne vehicles (UAVs).Computer-based modeling and execution systems are useful in the designof the aerospace and aeronautic systems, which demand high cost todesign and execute real systems. Moreover, automatic code generationfacilities support the implementation effort to arrive at embedded codefor production and rapid prototype testing. Among aerospace andaeronautic components, a planetary environment is a key element in thedesign of the aerospace and aeronautic systems.

Conventional modeling and execution systems provide component models andutilities to develop and integrate aerospace and aeronautic systemswhich include equations of motion models and planetary environmentmodels for atmosphere and wind. The models provided in the conventionalmodeling and execution systems are limited to standard day atmospheremodels, continuous wind turbulence models, and fixed mass equations ofmotion models. For more accurate design and execution of an aerospace oraeronautic system, non-standard day atmosphere models, discrete windturbulence models, and variable mass equations of motion models areneeded.

Furthermore, in the conventional systems, it is required to replace anatmosphere model to change between atmosphere models, to replace a windturbulence model to change between wind turbulence models, and toreplace equations of motion model to change between equations of motionmodels. Therefore, there is also a need to conveniently change acurrently incorporated atmosphere model, wind turbulence model, orequations of motion model to another atmosphere model, wind turbulencemodel, or equations of motion model.

SUMMARY OF THE INVENTION

The present invention provides methods and systems for the design andexecution of a target system in a computer-based modeling and executionenvironment. The target system of the present invention incorporatesmodels. The models include planetary environment models to take intoaccount the effect of the planetary environment on the target system andequations of motion models to account for the flight dynamics. Theplanetary environment models of the present invention mathematicallyrepresent planetary environment specifications, such as atmosphere andwind.

The present invention provides multiple atmosphere models includingstandard day atmosphere models and non-standard day atmosphere models.The present invention provides a user interface that displays an optionto select one of the atmosphere models. The user interface is providedin response to user's action, such as clicking the symbol representingthe atmosphere model. The user interface of the present inventionenables users to change a currently incorporated atmosphere model toanother atmosphere model without removing the current atmosphere modeland then adding another atmosphere model.

The present invention provides multiple wind turbulence models includingcontinuous wind turbulence models and discrete wind turbulence models.The present invention provides a user interface that displays an optionto select one of the wind turbulence models. The user interface isprovided in response to user's action, such as clicking the symbolrepresenting the wind turbulence model. The user interface of thepresent invention enables users to change a currently incorporated windturbulence model to another wind turbulence model without removing thecurrent wind turbulence model and then adding another wind turbulencemodel.

The present invention provides multiple equations of motion modelsincluding three-degree-of-freedom (3DoF) equations of motion models andsix-degree-of-freedom (6DoF) equations of motion models. The 3DoF and6DoF equations of motion models may provide models for equations ofmotion with variable mass. The variable mass includes at least one ofsimple variable mass in which mass changes via mass rate, and a customvariable mass in which users may specify how the mass changes. Thepresent invention provides a user interface that displays an option toselect one of the equations of motion models. The user interface of thepresent invention enables users to change a currently incorporatedequations of motion model to another equations of motion model withoutremoving the current equations of motion model and then adding anotherequations of motion model.

The user interface of the present invention may also be provided todisplay an option to select one of the models provided for a component,such as actuators, aerodynamics and propulsion models. For example, theuser interface enables users to change a current coordinate system toanother coordinate system.

In an illustrative embodiment of the present invention, a computer-basedmodeling and execution system is provided for the design of a targetsystem that includes at least one component model. The system includes amodel storage for storing and providing component models necessary todesign the target system. The component models include non-standard dayatmosphere models. The system also includes a design unit for designingthe target system by utilizing the models provided by the model storage.The design unit provides a user interface to select an atmosphere modelfrom the models in the model storage.

In another illustrative embodiment of the present invention, acomputer-based modeling and execution system is provided for the designof a target system that includes at least one component model. Thesystem includes a model storage for storing and providing componentmodels necessary to design the target system. The component modelsinclude discrete wind turbulence models. The system also includes adesign unit for designing the target system by utilizing the modelsprovided by the model storage. The design unit provides a user interfaceto select a wind turbulence model from the models in the model storage.

In still another illustrative embodiment of the present invention, acomputer-based modeling and execution system is provided for the designof a target system that includes at least one component model. Thesystem includes a model storage for storing and providing componentmodels necessary to design the target system. The component modelsinclude models for three-degree-of-freedom equations of motion withvariable mass and/or six-degree-of-freedom equations of motion withvariable mass. The system also includes a design unit for designing thetarget system by utilizing the models provided by the model storage. Thedesign unit provides a user interface to select one of the models forequations of motion with variable mass provided by the model storage.

In yet still another illustrative embodiment of the present invention, acomputer-readable medium holding instructions executable in a computerfor the design of a target system in which a planetary environment is anelement. Planetary environment models are provided to design the targetsystem wherein the planetary environment models include non-standard dayatmosphere models. A user interface is provided to incorporate anatmosphere model into the target system by selecting one of theatmosphere models including non-standard day atmosphere models.

In yet still another illustrative embodiment of the present invention, acomputer-readable medium holding instructions executable in a computerfor the design of a target system in which a planetary environment is anelement. Planetary environment models are provided to design the targetsystem wherein the planetary environment models include discrete windturbulence models. A user interface is provided to incorporate a windturbulence model into the target system by selecting one of the windturbulence models including discrete wind turbulence models.

In yet still another illustrative embodiment of the present invention, acomputer-readable medium holding instructions executable in a computerfor the design of a target system that includes at least one componentmodel. The component model includes the models forthree-degree-of-freedom equations of motion with variable mass and/orsix-degree-of-freedom equations of motion with variable mass. A userinterface is provided to incorporate one of the models for equations ofmotion with variable mass into the target system by selecting one of themodels for equations of motion with variable mass.

By providing standard day atmosphere models and non-standard dayatmosphere models, continuous wind turbulence models and discrete windturbulence models, and models of equations of motion with variable mass,the present invention can design and execute a target system moreaccurately than the conventional system that provides only standardatmosphere models, continuous wind turbulence models, and fixed massequations of motion. The present invention enables users to select anatmosphere model conveniently in a user interface that provides anoption to select one of atmosphere models. In addition, the presentinvention also enables users to select a wind turbulence modelconveniently in a user interface that provides an option to select oneof wind turbulence models. Moreover, the present invention furtherenables users to select equations of motion model conveniently in a userinterface that provides an option to select one of multiple equations ofmotion models.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram representation of an exemplary system formodeling and execution an aerospace or aeronautic system in anillustrative embodiment of the present invention;

FIG. 1B is a block diagram representation of an exemplary computersystem suitable for practicing the illustrative embodiment of thepresent invention depicted in FIG. 1A;

FIG. 2A is an exemplary computer display showing the categories ofaerospace and aeronautic component models provided from the modelstorage depicted in FIG. 1A;

FIG. 2B is an exemplary computer display showing the atmosphere modelsprovided from the model storage depicted in FIG. 1A;

FIG. 2C is an exemplary computer display showing the wind modelsprovided from the model storage depicted in FIG. 1A;

FIG. 2D is a computer display view showing an exemplary block diagramfor interpolating wind velocity in the transitional region;

FIG. 2E is an exemplary computer display showing the models ofthree-degree-of-freedom (3DoF) equations of motion provided from themodel storage depicted in FIG. 1A;

FIG. 2F is an exemplary computer display showing the models ofsix-degree-of-freedom (6DoF) equations of motion provided from the modelstorage depicted in FIG. 1A;

FIG. 3A is a computer display showing an exemplary block diagram of anaerospace or aeronautic system implemented in the illustrativeembodiment of the present invention;

FIG. 3B is a computer display showing an exemplary block diagram of theplanetary environment model incorporated into the aerospace oraeronautic system depicted in FIG. 3A;

FIG. 3C is a computer display showing an exemplary block diagram of thewind model depicted in FIG. 3B;

FIG. 4A is a computer display showing an exemplary graphical userinterface provided in response to the clicking of the atmosphere modeldepicted in FIG. 3B;

FIG. 4B is a computer display showing an exemplary graphical userinterface provided in response to the clicking of the wind turbulencemodel depicted in FIG. 3C;

FIG. 4C is a computer display showing an exemplary graphical userinterface provided in response to the clicking of the equations ofmotion model (3DoF);

FIGS. 4D-4E show a computer display showing an exemplary graphical userinterface provided in response to the clicking of the equations ofmotion model (6DoF) depicted in FIG. 3A;

FIG. 5A is a computer display showing an exemplary block diagram of thethree-degree-of-freedom (3DoF) equations of motion model in body axesdepicted in FIG. 2E;

FIG. 5B shows the replacement blocks for the Determine Force, Mass, &Inertia block depicted in FIG. 5A; and

FIGS. 5C-5E show illustrative block diagrams for the replacement blocksthat correspond to the fixed mass version, the simple variable massversion and the custom variable mass version of Determine Force, Mass, &Inertia block.

DETAILED DESCRIPTION

The illustrative embodiment of the present invention concerns acomputer-based modeling and execution system for the design andexecution of a target system. The system provides models that areincorporated into the target system to mathematically represent aportion or all of the target system. The models provided in theillustrative embodiment of the present invention include aerospace andaeronautic models that are useful in design and execution the targetsystem. The aerospace and aeronautic models may include planetaryenvironmental models, such as atmosphere models and wind models. Theatmosphere models include standard atmosphere models and non-standardday atmosphere models. The wind models include continuous windturbulence models and discrete wind turbulence models. The aerospace andaeronautic models may also include models of three-degree-of-freedomequations of motion with fixed or variable mass and models ofsix-degree-of-freedom equations of motion with fixed or variable mass.The models are represented by symbols or icons, such as blocks, with theindication of an external port or ports that can be of input or outputtype in the illustrative embodiment of the present invention.

The illustrative embodiment of the present invention provides a userinterface to enter the parameters of the atmosphere model incorporatedinto the target system. The user interface is provided in response to anaction taken by users who select the atmosphere model. The userinterface provides an option to select one of the multiple atmospheremodels including standard day atmosphere models and non-standard dayatmosphere models. The user interface enables users to change anatmosphere model to another atmosphere model without replacing thecurrent atmosphere model.

The illustrative embodiment of the present invention provides a userinterface to enter the parameters of the wind turbulence modelincorporated into the target system. The user interface is provided inresponse to an action taken by users who select the wind turbulencemodel. The user interface provides an option to select one of themultiple wind turbulence models including continuous wind turbulencemodels and discrete wind turbulence models. The user interface enablesusers to change a wind turbulence model to another wind turbulence modelwithout replacing the current wind turbulence model.

FIG. 1A is a block diagram representation depicting an exemplary system100 suitable for practicing an illustrative embodiment of the presentinvention. The system 100 includes a model storage 110, a design unit120, an execution unit 130 and a code generator 140. The model storage110 contains models for the design and execution of aerospace andaeronautic systems, such as aircraft, spacecraft, missiles, satellites,weapons, and unmanned airborne vehicles (UAVs). One of skill in the artwill appreciate that the aerospace and aeronautic systems areillustrative target systems and the target systems include any systemsthat incorporate planetary environment models in the design andexecution of the systems, such as climate prediction systems.

The model storage 110 provides aerospace and aeronautic component modelsto the design unit 120 and the execution unit 130 that incorporate thecomponent models into the aerospace and aeronautic systems. The modelstorage 110 includes planetary environment models for gravity,atmosphere, wind, etc. The planetary environment models are essentialelements in design and execution aerospace and aeronautic systems. Themodels provided from the model storage 110 are used in the design unit120 to create a new model of aerospace and aeronautic systems. The modelstorage 110 may also provides models of complete aerospace andaeronautic systems. The models of the complete aerospace and aeronauticsystems may be customized in the design unit 120 to a particularaerospace or aeronautic system. The aerospace and aeronautic systemcreated or customized in the system level design unit 120 using themodels in the model storage 110 is executed in the execution unit 130and the result of the execution can be analyzed to refine the design ofthe aerospace and aeronautic systems.

The models provided from the model storage 110 may be represented insymbols or icons, such as blocks, with the indication of an externalport or ports that can be of input or output type. These symbols can beincorporated directly into the aerospace and aeronautic systems designedand executed in the design unit 120 and the execution unit 130,respectively. One of skill in the art will appreciate that the modelsprovided from the model storage 110 can be represented in graphicalsymbols or textual symbols.

An illustrative embodiment of the model storage 110 can be found in theAerospace Blockset, from The MathWorks, Inc. of Natick, Mass. TheAerospace Blockset provides models and utilities for the development andintegration of aerospace and aeronautic systems and sub-system modelsfor the aerospace and aeronautic systems. One of skill in the art willappreciate that the Aerospace Blockset is an illustrative embodiment ofthe present invention and the model storage 110 of the present inventionis not limited to the Aerospace Blockset, and rather may include AeroSimBlockset, from Unmanned Dynamics of Hoover River, Oreg., AerospaceVehicle Library, from MDS Software of Santa Ana, Calif., AerospaceToolbox, from Miltec of Huntsville, Ala., and Aerospace Library, fromNational Instruments of Austin, Tex. The Aerospace Blockset operates inSimulink, from The MathWorks, Inc. of Natick, Mass., which provides aninteractive tool for designing, executing, synthesizing, and analyzingaerospace and aeronautic systems. Simulink integrates seamlessly withMATLAB, from The MathWorks, Inc. of Natick, Mass., providing immediateaccess to analysis and design tools.

The models provided from the model storage 110 can be written in M-code,C-code, FORTRAN, or any other code. If the models are written in adifferent code as the code implementing the design unit 120 and theexecution unit 130, the models are compiled to be executed in the designunit 120 and the execution unit 130. The Aerospace Blockset can be builton native Simulink blocks or S-functions which enable each of the modelsto operate in the Simulink environment model. S-functions written inC-code, for example, are compiled using the MEX command in MATLAB tomake a file that is executable in the Simulink environment.

The code generator 140 generates customizable C-code directly from theblock diagrams of the models designed in the design unit 120 to beexecuted in the execution unit 130. By automatically generating C-code,the code generator 140 enables rapid prototyping, hardware-in-the-loopsimulations, and desktop rapid simulation of the models designed in thedesign unit 120. The code generator 140 may generate efficient C-codefor embedded systems applications. One of skill in the art willappreciate that C-code is an illustrative code that is generated in thecode generator 140 and the code generator 140 may generate differentcode for the models, such as ADA. Real-Time Workshop® from TheMathWorks, Inc. of Natick, Mass., is an example of the code generator140.

FIG. 1B is a block diagram representation of a computer system suitablefor practicing the illustrative embodiment of the present inventiondepicted in FIG. 1A. The computer system 140 includes a secondary memory150, a primary memory 160, a μ-processor 170, a monitor 180 and akeyboard/mouse 190. The pt-processor 170 controls each component of thecomputer system 140 to run the software tools for modeling and executionan aerospace and aeronautic system properly. The computer system 140receives through the keyboard/mouse 190 data necessary for modeling andexecution the aerospace and aeronautic system, such as input data forthe type of the aerospace and aeronautic system. The computer system 140displays in the monitor 180 the result of modeling and execution theaerospace and aeronautic system. The primary memory 160 fetches from thesecondary memory 150 and provides to the pt-processor 170 the codes thatneed to be accessed quickly by the μ-processor 170 to operate thecomputer system and to run the modeling and execution system. Thesecondary memory 150 usually contains software tools for applications.The secondary memory 150 include, in particular, codes 151 for the modelstorage, codes 153 for the design and execution of the aerospace andaeronautic system, codes 155 for the analysis and refining of the designand execution.

Simulink, from The MathWorks, Inc. of Natick, Mass., provides codes forusers to design a block diagram of aerospace and aeronautic systems,execute the systems' behavior, analyze their performance, and refine thedesign. Simulink allows users to design aerospace and aeronautic systemsthrough a user-interface that allows drafting block diagram models ofthe aerospace and aeronautic systems. All of the model blocks in themodel storage 110 are available to users when the users are building theblock diagram of the aerospace and aeronautic systems. Individual usersmay be able to customize this model block e.g. by (a) reorganizingblocks in some custom format, (b) deleting blocks they do not use, and(c) adding custom blocks they have designed. The blocks may be draggedthrough some human-machine interface (such as a mouse or keyboard) fromthe model storage 110 on to the window (i.e., model canvas). Simulinkincludes a block diagram editor that allows users to perform suchactions as draw, edit, annotate, save, and print out block diagramrepresentations of aerospace and aeronautic systems. The block diagrameditor is a graphical user interface (GUI) component that allowsdrafting of block diagram models by users. In Simulink, there is also atextual interface with a set of commands that allow interaction with thegraphical editor. Using this textual interface, users may write specialscripts that perform automatic editing operations on the block diagram.Simulink also allows users to execute the designed aerospace andaeronautic systems to determine the behavior of the systems. Simulinkincludes a block diagram execution engine that carries out the task ofcompiling and linking the block diagram to produce an “in-memoryexecutable” version of the model that is used for generating code and/orexecuting a block diagram model. The underlying numericalrepresentations of models including data type, precision and datavectorization of the models are automatically derived from the contextof their use.

FIG. 2A is an exemplary computer display 210 showing the categories ofaerospace and aeronautic component models provided from the modelstorage 110 in the illustrative embodiment of the present invention. Themodels provided from the model storage 110 are used in the developmentof aerospace or aeronautic system and classified into categoriesaccording to the functions that the models perform. The models arecategorized into planetary environment models 211, equations of motionmodels 212, aerodynamics models 213, propulsion models 214, actuatormodels 215, etc. The planetary environment models 211 include atmospheremodels 216, wind models 218, gravity models 217. The atmosphere modelsand wind models are described below in more detail with reference toFIGS. 2B and 2C, respectively.

FIG. 2B is an exemplary computer display 220 showing the atmospheremodels belonging to the category of planetary environment models 211 inthe illustrative embodiment of the present invention. The atmospheremodels are represented by blocks in the illustrative embodiment of thepresent invention. One of skill in the art will appreciate that theatmosphere models can be represented by any other symbols or icons. Eachblock of the atmosphere models has an input, Height, and four outputsincluding Temperature, Speed of Sound, Air Pressure and Air Density. Theatmosphere models include an—International Standard Atmosphere (ISA)atmosphere model 221, a Committee on Extension to the StandardAtmosphere (COESA) U.S. atmosphere model 222, a Non-Standard Day 310atmosphere model 223, a Non-Standard Day 210C atmosphere model 224, anda Lapse Rate model 226. The ISA atmosphere model 221 and COESAatmosphere model 222 represent a standard day atmosphere andNon-Standard Day 310 atmosphere model 223 and Non-Standard Day 210Catmosphere model 224 represent a non-standard day atmosphere. In theillustrative embodiment of the present invention, the non-standard dayatmosphere includes any atmosphere other than the standard atmosphere.

The ISA atmosphere model 221 implements the mathematical representationof the international standard atmosphere values for absolutetemperature, pressure, density, and speed of sound for the inputgeopotential altitude. The COESA U.S. atmosphere model 222 implementsthe mathematical representation of the 1976 COESA U.S. standard loweratmospheric values for absolute temperature, pressure, density, andspeed of sound for the input geopotential altitude. The COESA atmospheremodel defines six layers from sea level to 71 km and uses equationsadopted in 1976 by COESA to determine the temperature, pressure anddensity at any altitude. The equations and parameters are documented ina book entitled U.S. Standard Atmosphere, 1976 published by the U.S.Government Printing Office, Washington, D.C.

In the illustrative embodiment, the Non-Standard Day 310 atmospheremodel 223 and Non-Standard Day 210C atmosphere model 224 implement thedata set forth in military standards MIL-HDBK-310 and MIL-STD-210C,respectively, for absolute temperature, pressure, density, and speed ofsound for the input geopotential altitude. The military standardsMIL-HDBK-310 and MIL-STD-210C include regional climate data in additionto the world wide data, in which the land areas of the world could bedivided into 4 regional types of climate based on temperaturedifferences. The military standards MIL-HDBK-310 and MIL-STD-210Cprovide long-term climate extremes that are expected to occur at leastonce, for a short duration, during 10, 30, or 60 years of exposure. Theextremes in the standard MIL-HDBK-310 replace the extremes in thestandard MIL-STD-210C. The standards MIL-HDBK-310 and MIL-STD-210C alsoprovide consistent vertical profiles of temperature and density up to 80km based on extremes at 5, 10, 20, 30 and 40 km. The input of the modelsis geopotential height and the four outputs are temperature, speed ofsound, air pressure, and air density. The military standardsMIL-HDBK-310 and MIL-STD-210C are illustrative standards for theembodiment of non-standard day atmosphere models. One of skill in theart will appreciate that the non-standard day atmosphere models are notlimited to the military standards MIL-HDBK-310 and MIL-STD-210C, andrather includes any specification describing an atmosphere other thanthe standard atmosphere.

The COESA atmosphere model 222, Non-Standard Day 310 atmosphere model223 and Non-Standard Day 310 atmosphere model 224 are tied together by adotted line 225 to indicate that the three models are provided togetherin a user interface and one of the models can be selected by the user.The user interface is described below in more detail with reference toFIG. 4A.

FIG. 2C is an exemplary computer display 230 showing the wind modelsbelonging to the category of the planetary environment models 211depicted in the illustrative embodiment of the present invention. Thewind models are represented by blocks in the illustrative embodiment ofthe present invention. Each block of the wind models has an externalport or ports that can be of input or output type. One of skill in theart will appreciate that the wind models can be represented by any othersymbols or icons. The wind models include wind turbulence models 231, awind gust model 237, a wind shear model 238 and a horizontal wind model239. The illustrative embodiment of the present invention providesmultiple wind turbulence models 231 including continuous Von Karman windturbulence model 232, continuous Dryden wind turbulence model 233 anddiscrete Dryden wind turbulence models 234 through 236. The multiplewind turbulence models 232 through 236 are tied together by a dottedline 231 to indicate that the wind turbulence models 232 through 236 areprovided to users in a user interface that displays an option to selectone of the wind turbulence models 232 through 236 tied together. Theuser interface is described in more detail with reference to FIG. 4B.

The wind models of the illustrative embodiment of the present inventionimplement the mathematical representation in the military specificationsMIL-F-8785C and MIL-STD-1797 which contain the requirements for theflying and ground handling quality of military aerospace and aeronauticsystems. The specifications are intended to assure flying qualities forthe adequate mission performance and flight safety regardless of thedesign implementation or flight control system augmentation. Thespecifications MIL-F-8785C and MIL-STD-1797 provide atmosphericturbulence forms including Von Karman form and Dryden form, discretewind gust form and wind shear form. The specification MIL-STD-1797additionally provides the digital filter implementation of the Drydenturbulence components. Turbulence can be considered as a stochasticprocess defined by velocity spectra. The military specifications use thecontinuous Von Karman turbulence model and when the use of thecontinuous Von Karman turbulence model is not feasible, the Dryden windturbulence model is allowed to be used. The wind turbulence models 232through 236 use the Dryden spectral representation to add turbulence tothe aerospace or aeronautic model by passing band-limited white noisethrough appropriate forming filters. One of skill in the art willappreciate that the wind turbulence models are not limited to themilitary specifications MIL-F-8785C and MIL-STD-1797, and ratherincludes any continuous and discrete wind turbulence models.

The wind turbulence models 231 of the illustrative embodiment of thepresent invention implement both the low and medium/high altitude modelsfrom the military specifications MIL-F-8587C and MIL-HDBK-1797. The lowand medium/high altitudes are defined as altitudes below 1000 feet andabove 2000 feet, respectively. The wind turbulence models 231 of theillustrative embodiment of the present invention provide wind turbulencemodels for the transition region between the low and medium/highaltitudes, i.e. an altitude above 1000 feet and below 2000 feet, whichis not defined within the military specification MIL-F-8587C andMIL-HDBK-1797. In order to provide a turbulence model that is continuousin altitude, a transition method is required to determine the values forthe wind turbulence models in the transition region. A transition methodcan consist of linearly interpolating between the values of the windturbulence models at the boundary altitudes, that is, 1000 feet and 2000feet. For example, the turbulence velocities and turbulence angularrates are determined by the specifications provides in the militaryspecification MIL-F-8587C and MIL-HDBK-1797 at the altitudes of 1000feet and 2000 feet. The values for the wind turbulence model in thetransition region are generated by linearly interpolating between thevalue from the low altitude model at 1000 feet transformed from meanhorizontal wind coordinates to body coordinates and the value from thehigh altitude model at 2000 feet in body coordinates. Users can choosestability coordinate systems instead of the body coordinates. One ofskill in the art will appreciate that the coordinate system of theregion may be implemented in other coordinates, such as earthcoordinates. FIG. 2D is a computer display view 240 showing an exemplaryblock diagram for interpolating wind velocity in the transitionalregion. The signal 241 is a bus signal that contains both themedium/high velocity 243 and low altitude velocity 242. The low altitudevelocity 242 is applied to a wind to body transformation block 244 totransform the wind coordinates of the low velocity 242 to bodycoordinates. The velocity 246 in the transition region is generated bylinearly interpolating between the transformed low velocity 245 and themedium/high velocity 243. This method also applies to the angular rates.One of skill in the art will appreciate that the transition region andtransition method are not limited to a single region and method.

FIG. 2E is an exemplary computer display 250 showing the models forthree-degree-of-freedom (3DoF) that belong to the equations of motion212 depicted in FIG. 2A of the illustrative embodiment of the presentinvention. The 3DoF models are represented by blocks in the illustrativeembodiment of the present invention. Each block of the 3DoF models hasexternal ports that can be of input or output type. One of skill in theart will appreciate that the 3DoF models can be represented by any othersymbols or icons. The 3DoF models include a Fixed Mass 3DoF in Body Axesmodel 251, a Simple Variable Mass 3DoF in Body Axes model 252 and aCustom Variable Mass 3DoF in Body Axes model 253. The 3DoF models 251through 253 implement three-degree-of-freedom equations of motion inbody axes. One of skill in the art will appreciate that the 3DoF models251 through 253 may be implemented within other axes, such as wind axes.The 3DoF models 251 through 253 are also implemented with differenttypes of mass including fixed mass, simple variable mass and customvariable mass. The mass does not change in the type of the fixed mass.The mass changes via a mass rate in the simple variable mass. In thecustom variable mass, users may specify in detail how the mass changesand other parameters that are closely dependent on the mass change. Theillustrative embodiment of the present invention provides multiple 3DoFmodels 251 through 253 including Variable Mass 3DoF models 252-253. Themultiple 3DoF models 251-253 are provided to users in a user interfacethat displays an option to select one of the 3DoF models 251 through253. The user interface is described in more detail with reference toFIG. 4C.

FIG. 2F is an exemplary computer display 260 showing the models forsix-degree-of-freedom (6DoF) equations of motion that belong to theequations of motion block 212 depicted in FIG. 2A of the illustrativeembodiment of the present invention. The 6DoF models are represented byblocks in the illustrative embodiment of the present invention. Eachblock of the 6DOF models has external ports that can be of input oroutput type. One of skill in the art will appreciate that the 6DoFmodels can be represented by any other symbols or icons. The 6DoF modelsinclude a Fixed Mass 6DoF using Euler Angles 261 and Fixed Mass 6DoFusing Quaternion 262. The 6DoF models also include a Simple VariableMass 6DoF using Euler Angles 263 and a Simple Variable Mass 6DoF usingQuaternion 264. The 6DoF models further include a Custom Variable Mass6DoF using Euler Angles 265 and a Custom Variable Mass 6DoF usingQuaternion 266. The 6DoF models using Euler Angles 261, 263 and 265implement an Euler Angle representation of six-degrees-of-freedomequations of motion. The 6DoF models using Quaternion 262, 264 and 266implement a quaternion representation of six-degrees-of-freedomequations of motion. The 6DoF models 261 through 266 implementsix-degree-of-freedom equations of motion within body axes. One of skillin the art will appreciate that the 6DoF models 261 through 266 may beimplemented within other axes, such as wind axes. The 6DoF models 261through 266 also implement different types of mass including fixed mass,simple variable mass and custom variable mass. The mass does not changein the type of the fixed mass. The mass changes via a mass rate in thesimple variable mass type. In the type of custom variable mass, usersmay specify in detail how the mass changes and other parameters that areclosely dependent on the mass change. The illustrative embodiment of thepresent invention provides multiple 6DoF models 261-266 includingVariable Mass 6DoF models 263-266. The multiple 6DoF models 261-266 areprovided to users in a user interface that displays an option to selectone of the 6DoF models 261 through 266. The user interface is describedin more detail with reference to FIGS. 4D and 4F.

FIG. 3A is a computer display 310 showing a block diagram of anexemplary aerospace and aeronautic system implemented in theillustrative embodiment of the present invention. A complete blockdiagram of the aerospace and aeronautic system may be provided from themodel storage 110 and customized by users in the design unit 120 to aparticular aerospace and aeronautic system. The block diagram of theaerospace and aeronautic system can also be drawn by the users in thedesign unit 120 using the models in the model storage 110. The blockdiagram shown in FIG. 3A is illustrative and can be varied depending onthe aerospace and aeronautic system.

The aerospace and aeronautic system shown in FIG. 3A is a typicalaerospace and aeronautic system that includes a number of components,such as a model 311 for equations of motion (3DoF or 6DoF), an planetaryenvironment model 313, an aerodynamics model including a model 315 forpre-calculation, a coefficient calculation model 317 and force andmoment calculation model 319. If users select the planetary environmentmodel 313 by, for example, clicking on the block of the planetaryenvironment model 313, a detailed block diagram of the planetaryenvironment model 313 is displayed in another window, such as a pop-upwindow. Clicking the block of the planetary environment model 313 is anillustrative way to select the planetary environment model 313. One ofskill in the art will appreciate that the planetary environment model313 can be selected by another way.

FIG. 3B is an illustrative computer display 320 showing a detailed blockdiagram of the planetary environment model 313 depicted in FIG. 3A. Theplanetary environment model 313 includes a wind model 321, an atmospheremodel 323 and a gravity model 325. The detailed block diagram of theplanetary environment model 313 shown in FIG. 3B is an illustrativeembodiment of the present invention and can be varied depending on thestructure of the aerospace and aeronautic system.

If users click on the block of the atmosphere model 323, a userinterface is provided for entering parameters of the atmosphere model323. The user interface is displayed besides or over the block 323 inthe same window. One of skill in the art will appreciate that the userinterface can be provided in a different manner, such as being providedin a separate pop-up window. FIG. 4A is a computer display showing anillustrative graphical user interface 410 provided in response to theclicking of the atmosphere model 323 depicted in FIG. 3B. The graphicaluser interface 410 provides two sections. One of the sections describesthe atmosphere model incorporated into the aerospace and aeronauticsystem and the other section enters parameters of the atmosphere modelwhich include units and specification. The graphical user interface 410shown in FIG. 4A is illustrative and one of skill in the art willappreciate that other types of user interfaces can be provided to enterparameters of the atmosphere models, such as textual user interfaces.The graphical user interface 410 provides menus to select units andspecifications, respectively. If the users click the button of theunits, the users can select units between metric and English units, forexample. If the user clicks the button 411 of the specification, thegraphical user interface 410 provides atmosphere models that areprovided from the model storage 110. The models provided in the menu 413includes 1976 COESA U.S. Standard Atmosphere, MIL-HDBK 310 andMIL-STD-210C, which corresponds to the atmosphere models tied togetherby dotted line 222 in FIG. 2B. The atmosphere models provided in themenu 413 may be extended by users so that users may add to the menu 413another atmosphere model. If the users select one of the atmospheremodels provided at the menu 413, the selected model is incorporated fromthe model storage 110 into the aerospace and aeronautic system that theuser designs and executes. The menu 413 shown in FIG. 4A is illustrativeand one of skill in the art will appreciate that the units andspecifications can be selected in a different manner.

If users select the wind model 321 by, for example, clicking on theblock of the wind model 313, a detailed block diagram of the wind model321 is displayed in a window, such as a pop-up window. FIG. 3C is anillustrative computer display 330 showing a detailed block diagram ofthe wind model 321 depicted in FIG. 3B. The wind model 321 in theillustrative embodiment of the present invention includes a wind shearmodel 331, a wind turbulence model 333 and a wind gust model 335. One ofskill in the art will appreciate that the wind model can have varioustypes of block diagrams and includes more or less models, such asbackground wind models, depending on the structure of the aerospace andaeronautic system.

If users click on the wind turbulence model 331, a user interface isprovided besides or over the block of the wind turbulence model 331 forentering parameters of the wind turbulence model. One of skill in theart will appreciate that the user interface can be provided in adifferent manner, such as being provided in a separate window. FIG. 4Bshows an illustrative computer display of the graphical user interface420 provided in response to the users' clicking of the wind turbulencemodel 331 depicted in FIG. 3C. The graphical user interface 420 providesblanks for entering parameters including model type, units, wind speed,wind direction, etc. In order to enter the model type, the graphicaluser interface provides a menu 423 in response to clicking a button 421.The menu includes the wind turbulence models that are provided from themodel storage. The wind turbulence models provided in the menu 423includes continuous Von Karman, continuous Dryden and discrete Dryden,which correspond to the wind turbulence models tied together by thedotted line 231 in FIG. 2C. The wind turbulence models provided in themenu 423 may be extended by users so that users may add to the menu 423another wind turbulence model. If the user select of the wind turbulencemodels provided at the menu 423, the selected wind turbulence model isincorporated from the model storage 110 into the aerospace andaeronautic system the users design and execute.

If users click on the model 311 for equations of motion that represents6DoF, a user interface is provided for entering parameters of the 6DoFmodel. FIGS. 4D and 4E shows an illustrative computer display of thegraphical user interface 450 provided in response to the users' clickingof the 6DoF model 311 depicted in FIG. 3A. The graphical user interface450 provides blanks for entering parameters including units, mass type,presentation, etc. In order to enter the mass type, the graphical userinterface provides a menu 443 in response to clicking a button 441. Themenu includes the fixed, simple variable and custom variable types. InFIG. 4E, in order to enter the representation, the graphical userinterface 450 provides a menu 453 in response to clicking a button 451.The combination of the mass type and the representation provide the 6DoFmodels depicted in FIG. 2F. The 6DoF models provided by the combinationof the mass type and the representation in the menus 443 and 453 may beextended by users so that users may add to the menus 443 and 453 another6DoF model. If the user selects a 6DoF models provided at the menus 443and 453, the selected 6DoF model is incorporated from the model storage110 into the aerospace and aeronautic system that the users design andexecute.

Assuming that the model 311 represents a 3DoF model instead of a 6DoFmodel, a user interface is provided for entering the parameters of the3DoF model as shown in FIG. 4C. FIG. 4C is an illustrative computerdisplay of the graphical user interface 430 provided for entering theparameters of the 3DoF model depicted in FIG. 2E. The graphical userinterface 430 provides blanks for entering parameters including units,mass type, etc. In order to enter the mass type, the graphical userinterface provides a menu 433 in response to clicking a button 431. Themenu includes the fixed, simple variable and custom variable types,which correspond to the 3DoF models depicted in FIG. 2E. The mass doesnot change in the fixed mass. The mass changes via a mass rate in thesimple variable mass. In the custom variable mass, users may specify indetail how the mass changes and other parameters that are closelydependent on the mass change. The 3DoF models provided in the menu 433may be extended by users so that users may add to the menu 433 another3DoF model. If the user select of the 3DoF models provided at the menu433, the selected 3DoF model is incorporated from the model storage 110into the aerospace and aeronautic system that the users design andexecute.

Upon selecting the desired component model from one of the userinterfaces depicted in FIGS. 4A through 4E, the correspondingfunctionality of the desired component model can be included in thesymbol representing the models in a number of ways: (i) one of aselection of pre-built components models can be copied or referred to inthe symbol, (ii) the desired functionality can be included byconditionally evaluating part of a component model, and (iii) a sequenceof component model modifications can be executed to arrive at thedesired functionality. The first method represents a standard mechanismused in computer modeling and simulation packages such as Simulink.

The second method is illustrated, in the preferred embodiment, byexploiting a programming language which conditionally executes code withthe desired functionality in the following code snippet:

switch (type){

case COESA:

/* call COESA calculations */

CalcAtmosCOESA(alt,T,P,rho,SoS,k);

break;

case MILHDBK310:

{/* call MIL-HDBK-310 particular model */

switch(model){

case PROFILE:

CalcAtmosProfile310(alt,t_tab,dens_tab,T,P,rho,SoS,k);

break;

case ENVELOPE:

CalcAtmosEnvelope310(alt,alt_tab,temp_tab,dens_tab,pres_tab,T,P,rho,SoS,k);

break;

default:

ssSetErrorStatus(S, Mmsg);

goto EXIT_POINT;

}

}

break;

case MILSTD210C:

{/* call MIL-STD-210C particular model */

switch(model){

case PROFILE:

CalcAtmosProfile210c(alt,temp_tab,dens_tab,T,P,rho,SoS,k);

break;

case ENVELOPE:

CalcAtmosEnvelope210c(alt,alt_tab,temp_tab,dens_tab,pres_tab,T,P,rho,SoS,k,udata);

break;

default:

ssSetErrorStatus(S, Mmsg);

goto EXIT_POINT;

}

}

break;

default:

ssSetErrorStatus(S, Smsg);

goto EXIT_POINT;

}

Here the C code is partitioned to allow executing one of the availablebehaviors. To this end, the available functionality is embodied byconditionally executed code, in the example it is guarded by a casestatement. When the model component is evaluated, an indexing scheme isexploited to ensure the desired functionality as selected by the user isexecuted. Another embodiment would be to use native Simulink blocks toconditionally execute portions of the model.

In the third approach, a component model can be dynamically modified inresponse to selections from the user interface. In the preferredembodiment, a scripting language is exploited that, e.g., adds, removes,changes parameters, and connects blocks together to comprise the desiredfunctionality. This is illustrated in FIGS. 5A through 5E. FIG. 5A showsan illustrative block diagram 500 of the three-degree-of-freedom (3DoF)equations of motion model in body axes depicted in FIG. 2E. The blockdiagram 500 includes a Determine Force, Mass, & Inertia block 510 fordetermining the force, mass, and inertia of the body. FIG. 5B shows the“replacement blocks” 520-540 for the Determine Force, Mass, & Inertiablock 510 depicted in FIG. 5A. FIGS. 5C-5E show illustrative blockdiagrams for the replacement blocks 520-540 that correspond to the fixedmass version, the simple variable mass version and the custom variablemass version of Determine Force, Mass, & Inertia block 510,respectively, The following script commands modify a Fixed Mass 3DoF inBody Axes model to a Custom Variable Mass 3DoF in Body Axes model inresponse to the user selecting a Custom Variable Mass 3DoF in Body Axescomponent model:

function updatemodel(blk)

% get model type from user interface

tmode=get_param(blk;‘mtype’);

switch tmode

% replace how force, inertia and mass calculations take place for 3DoF

% depending on user interface

case ‘Fixed’

replaceblock([blk sprintf(‘/Determine Force, \nMass & Inertia’)], . . .

‘Mass & Inertia (fixed)’,‘aerolib3dofsys’);

case ‘Simple Variable’

replaceblock([blk sprintf(‘/Determine Force, \nMass & Inertia’)], . . .

‘Mass & Inertia (simple)’,‘aerolib3dofsys’);

case ‘Custom Variable’

replaceblock([blk sprintf(‘/Determine Force, \nMass & Inertia’)], . . .

‘Mass & Inertia (custom)’,‘aerolib3dofsys’);

otherwise

error(‘aeroblks:aeroblk3dofbody:invalidtype’,‘mass type not defined’);

end

return

The user interfaces depicted in FIGS. 4A through 4E may also be appliedto display an option to select one of the models provided for otheraerospace and aeronautic component, such as actuators 215 and propulsion214 models. For example, the user interface may be used to enable usersto change a currently incorporated actuator model to another actuatormodel, or to change a currently incorporated propulsion model to anotherpropulsion model. In these applications, the models provided in the userinterface for the users to select may be extended by the users so thatthe users may add models to the user interface.

In summary, the illustrative embodiment of the present inventionprovides software tools for the system level design and execution ofaerospace and aeronautic systems. The illustrative embodiment of thepresent invention provides multiple atmosphere models, includingstandard atmosphere models and non-standard day atmosphere models,multiple wind turbulence models, or multiple equations of motion models.The illustrative embodiment of the present invention also providesgraphical user interfaces in response to users' action for selecting amodel from the multiple atmosphere models, wind turbulence models, orequations of motion models. The graphical user interface enables usersto change the atmosphere model, wind turbulence model, equations ofmotion model to another atmosphere model, wind turbulence model orequations of motion model. The illustrative embodiment of the presentinvention therefore designs and executes an aerospace and aeronauticsystem more accurately and conveniently than conventional tools.

It will thus be seen that the invention attains the objectives stated inthe previous description. Since certain changes may be made withoutdeparting from the scope of the present invention, it is intended thatall matter contained in the above description or shown in theaccompanying drawings be interpreted as illustrative and not in aliteral sense. For example, the illustrative embodiment of the presentinvention may be practiced in any other model storage, such as a modelstorage that provides multiple models for the design and execution of anaerospace and aeronautic system. Practitioners of the art will realizethat the sequence of steps and architectures depicted in the figures maybe altered without departing from the scope of the present invention andthat the illustrations contained herein are singular examples of amultitude of possible depictions of the present invention.

I claim:
 1. A tangible computer-readable non-transitory storage mediumstoring instructions that, when executed on a processor, cause theprocessor to: identify a first icon in a graphical model representing atarget system, the first icon representing a component model of thetarget system, the component model having a plurality of configurations;select a first configuration for the component model from the pluralityof configurations; incorporate the first configuration for the componentmodel into the graphical model through the first icon; save thegraphical model that includes the first icon representing the firstconfiguration of the component model in a memory; select a secondconfiguration for the component model from the plurality ofconfigurations; dynamically modify, in the graphical model, the firsticon from representing the first configuration of the component model torepresenting the second configuration of the component model, where thedynamically modifying occurs without removing the saved graphical modelfrom the memory; and incorporate the second configuration of thecomponent model into the graphical model through the first icon afterthe second configuration is selected, the incorporating including:copying or referring to the second configuration using the first icon,or executing a sequence of modifications to the first icon to representthe second configuration using the first icon.
 2. The medium of claim 1,further storing instructions that, when executed on die processor, causethe processor to: visually indicate which configuration of the componentmodel is represented by the first icon using textual cues.
 3. The mediumof claim 1, further storing instructions that, when executed on theprocessor, cause the processor to: visually indicate which configurationof the component model is represented by the first icon using graphicalcues.
 4. The medium of claim 1 wherein the plurality of configurationsof the component model belongs to a category of atmosphere models thatinclude at least a non standard day atmosphere model.
 5. The medium ofclaim 1 wherein the plurality of configurations of the component modelbelongs to a category of wind turbulence models that include at least adiscrete turbulence model.
 6. The medium of claim 1 wherein theplurality of configurations of the component model belongs to a categoryof equations of motion models that include at least one simple variablemass model and at least one custom variable mass model.
 7. The medium ofclaim 1 wherein the first configuration of the component model has sameexternal ports that can be of input or output type as the secondconfiguration of the component model.
 8. The medium of claim 1 whereinthe first configuration of the component model has different externalports that can be of input or output type than the second configurationof the component model.
 9. The medium of claim 1 wherein the first iconrepresents one of the first configuration and the second configurationof the component model based on selecting the first configuration andthe second configuration.
 10. The medium of claim 1 wherein the firstconfiguration for the component model or the second configuration forthe component model is incorporated into the graphical model using ascript.
 11. A tangible computer-readable non-transitory storage mediumstoring instructions that, when executed on a processor, cause theprocessor to: select a first block representing a component model in ablock diagram model of a target system, the component model having aplurality of component model types; select a first component model typefrom the plurality of component model types; incorporate the firstcomponent model type into the block diagram model of the target systemthrough the first block; save the block diagram model of the targetsystem that includes the first component model type in a memory; selecta second component model type from the multiple component model types;dynamically modify, in the block diagram model, the first block torepresent the second component model type in response to selecting thesecond component model type, where the dynamically modifying occurswithout removing the saved block diagram model from the memory; andincorporate the second component model type into the block diagram modelof the target system, the incorporating including: copying or referringto the second component model type using the first block in the blockdiagram model, or executing a sequence of modifications to the firstblock to represent the second component model type using the first blockin the block diagram model.
 12. The medium of claim 11 wherein thecomponent model types belong to a category of atmosphere models thatinclude at least a non standard day atmosphere model.
 13. The medium ofclaim 11 wherein the component model types belong to a category of windturbulence models that include at least a discrete turbulence model. 14.The medium of claim 11 wherein the component model types belong to acategory of equations of motion models that include at least one simplevariable mass model and at least one custom variable mass model.
 15. Themedium of claim 11 wherein the first component model type has a sameconfiguration of external ports that can be of input or output type asthe second component model type.
 16. The medium of claim 11 wherein thefirst component model type has a different configuration of externalports that can be of input or output type as the second component modeltype.
 17. The medium of claim 11 wherein the first block represents oneof the first component model type and the second component model typedepending on selecting the first component model type and the secondcomponent model type.
 18. The medium of claim 11 wherein the firstcomponent model type is switched to the second component model typewithout replacing the first block by a second block representing thesecond component model type.
 19. The medium of claim 11, further storinginstructions that, when executed on a processor, cause the processor to:visually differentiate the first block from a remainder of blocks of theblock diagram model to indicate that the first block is configured torepresent one of the plurality of component model types.
 20. The mediumof claim 11 wherein the first component model type or the secondcomponent model type is incorporated into the block diagram model usinga script.
 21. A computer-implemented system comprising: a processor forexecuting: a model storage for storing and providing one or morecomponent models necessary to design a target system, a design unit fordesigning a graphical model representing the target system by utilizingthe one or more component models provided by the model storage, and auser interface for receiving a parameter for the one or more componentmodels of the target system, the parameter including a model type or amodel configuration for at least one of the one or more componentmodels, where the design unit dynamically modifies the at least one ofthe one or more component models in the graphical model to represent theparameter received by the user interface, the parameter beingincorporated into the graphical model by: copying or referring to theparameter using the at least one of the one or more component models inthe graphical model, or executing a sequence or modifications to the atleast one of the one or more component models to represent the parameterusing the at least one of the one or more component models in thegraphical model; and a memory for storing the graphical model includingthe one or more component models, where the dynamically modifying occurswithout removing the stored graphical model from the memory.
 22. Thesystem of claim 21 further comprising an execution unit for executingthe target system designed in the design unit.
 23. The system of claim22 wherein the execution unit is realized through a process of automaticcode generation from the design unit.
 24. The system of claim 21 whereinthe user interface is provided in response to selecting one of the oneor more component models of the target system.
 25. The system of claim21 wherein the user interface provides an option to select one of theone or more component models from the model storage.
 26. The system ofclaim 25 wherein the selected one of the one or more component modelsfrom the model storage is provided in the user interface.
 27. Acomputer-implemented method comprising: identifying a first icon in agraphical model representing a target system, the first iconrepresenting a component model of the target system, the component modelhaving a plurality of configurations; selecting a first configurationfor the component model from the plurality of configurations;incorporating the first configuration for the component model into thegraphical model through the first icon; saving the graphical model thatincludes the first icon representing the first configuration of thecomponent model in a memory; selecting a second configuration for thecomponent model from the plurality of configurations; and dynamicallymodifying, in the graphical model, the first icon from representing thefirst configuration of the component model to representing the secondconfiguration of the component model, where the dynamically modifyingoccurs without removing the saved graphical model from the memory; andincorporating the second configuration of the component model into thegraphical model through the first icon after the second configuration isselected, the incorporating including: copying or referring to thesecond configuration using the first icon, or executing a sequence ofmodifications to the first icon to represent the second configurationusing the first icon.
 28. The method of claim 27, further comprising:visually indicating which configuration of the component model isrepresented by the first icon using textual cues.
 29. The method ofclaim 27, further comprising: visually indicating which configuration ofthe component model is represented by the first icon using graphicalcues.
 30. The method of claim 27 wherein the plurality of configurationsof the component model belongs to a category of atmosphere models thatinclude at least a non standard day atmosphere model.
 31. The method ofclaim 27 wherein the plurality of configurations of the component modelbelongs to a category of wind turbulence models that include at least adiscrete turbulence model.
 32. The method of claim 27 wherein theplurality of configurations of the component model belongs to a categoryof equations of motion models that include at least one simple variablemass model and at least one custom variable mass model.
 33. The methodof claim 27 wherein the first configuration of the component model hassame external ports that can be of input or output type as the secondconfiguration of the component model.
 34. The method of claim 27 whereinthe first configuration of the component model has different externalports that can be of input or output type than the second configurationof the component model.
 35. The method of claim 27 wherein the firsticon represents one of the first configuration and the secondconfiguration of the component model depending on selecting the firstconfiguration and the second configuration.
 36. The method of claim 27wherein the first configuration for the component model or the secondconfiguration for the component model is incorporated into the graphicalmodel using a script.
 37. A computer-implemented method comprising:selecting a first block representing a component model in a blockdiagram model of a target system, the component model having a pluralityof component model types; selecting a first component model type fromthe plurality of component model types; incorporating the firstcomponent model type into the block diagram model of the target systemthrough the first block; saving the block diagram model of the targetsystem that includes the first component model type in a memory;selecting a second component model type from the multiple componentmodel types; dynamically modifying, in the block diagram model, thefirst block to represent the second component model type in response toselecting the second component model type, where the dynamicallymodifying occurs without removing the save block diagram model from thememory; and incorporating the second component model type into the blockdiagram model of the target system, the incorporating including: copyingor referring to the second component model type using the first block inthe block diagram model, or executing a sequence of modifications to thefirst block to represent the second component model type using the firstblock in the block diagram model.
 38. The method of claim 37 wherein thecomponent model types belong to a category of atmosphere models thatinclude at least a non standard day atmosphere model.
 39. The method ofclaim 37 wherein the component model types belong to a category of windturbulence models that include at least a discrete turbulence model. 40.The method of claim 37 wherein the component model types belong to acategory of equations of motion models that include at least one simplevariable mass model and at least one custom variable mass model.
 41. Themethod of claim 37 wherein the first component model type has a sameconfiguration of external ports that can be of input or output type asthe second component model type.
 42. The method of claim 37 wherein thefirst component model type has a different configuration of externalports that can be of input or output type as the second component modeltype.
 43. The method of claim 37 wherein the first block represents oneof the first component model type and the second component model typedepending on selecting the first component model type and the secondcomponent model type.
 44. The method of claim 37 the first componentmodel type is switched to the second component model type withoutreplacing the first block by a second block representing the secondcomponent model type.
 45. The method of claim 37, further comprising:visually differentiating the first block from a remainder of blocks ofthe block diagram model to indicate that the first block is configuredto represent one of the plurality of component model types.
 46. Themethod of claim 37 wherein the first component model type or the secondcomponent model type is incorporated into the block diagram model usinga script.